Rockstar has built its own engine since 2006 and shows no sign of stopping. RAGE - the Rockstar Advanced Game Engine - powered GTA IV, Red Dead Redemption, GTA V and Red Dead Redemption 2, and GTA 6 continues that line. What Rockstar has not done is publish a technical breakdown, so everything below is read off the footage.
What looks substantially rebuilt
Lighting
The showcase leans on bounced light and volumetrics in a way Red Dead 2 did not. Interiors lit through windows, wet streets reflecting neon, and night scenes that keep detail in shadow rather than crushing to black all point at a reworked lighting pipeline.
Crowds
The pedestrian density in beach and street scenes is the most visible jump. More importantly, individuals in those crowds behave differently from each other - this is a behaviour system, not just a higher spawn count.
Water
A game set on this coast has to get water right, and the footage shows surf, shallow flats and storm-driven flooding behaving differently from each other. RDR 2’s water was already strong; this looks like a further pass.
Streaming
Interiors that open without a loading break, and long drives between regions with no pause, indicate the streaming system was rebuilt around console SSDs from the start.
What about Euphoria?
Rockstar has used NaturalMotion’s Euphoria middleware for character physics since GTA IV, giving the series its distinctive stumbling ragdolls. Character reactions in the showcase look consistent with an evolved version of that, though Rockstar has not named it.
A caution on version numbers
You will see “RAGE 9” and similar labels in articles. Rockstar does not publicly version its engine. Those numbers are invented for headlines.
Performance questions are covered in our frame rate answer, and the videos themselves are on the trailers page.